Spectrally sensitized silver halide photographic emulsion

ABSTRACT

The invention concerns a silver halide photographic emulsion containing at least one sensitizing carbocyanine dye wherein an acetylamino group is present at the 5-position of the benzothiazole or benzoselenazole nucleus and the N-substituent of another benzothiazole or benzoselenazole nucleus is a sulfoalkyl group.

United States Patent [191 Sato et al.

[ SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION [75] Inventors: Akira Sato; Tadashi Ikecla; Keisuke Shiba; Haruo Takei. all of Kanagawa. Japan [73} Assignee: Fuji Photo Film Co., Ltd..

Kanagawa. Japan [22] Filed: Feb. 4. 1974 [21] Appl. No: 439.687

Related US. Application Data [63} Continuation-impart of Ser, No. 182.505. Sept. 21.

197 l. abandoned.

[30] Foreign Application Priorit Data Sept. 21. 1970 Japan 45-81768 [52] US. Cl. 96/137 [5|] lnt. CL", G03C H18 [451 Nov. 11, 1975 Primuri' Emminew-J. Travis Brown Armrne Agent. or FirmSughrue. Rothwell. Mion. Zinn and Mucpeak [5 7] ABSTRACT The invention concerns a silver halide photographic emulsion containing at least one sensitizing carboqa' nine dye wherein an zicetylamino group is present at the 5position of the benzothinzole or henzoselenazole nucleus and the N-substituent of another benzothiuzole or benzoselenuzole nucleus is u sulfoallql group.

5 Claims. 1 Drawing Figure Additional substituents of the type commonly used in the sensitizing carbocyanine dye art may also be present on the benzthiazole or benzselenazole nuclei. The presence and identity of these additional substituents is not of particular importance to the invention, the critical elements of the compound being the S-acetylamino substituent and the N-sulfoalkyl group on the opposite heterocyclic nucleus; provided, however, that the N- substituent on the heterocyclic nucleus carrying the 5- acetylamino group may not be sulfoalkyl. Further, the trimethine chain linking the heterocyclic nuclei may be meso-substituted preferably with a lower alkyl group having from 2 to 4 carbon atoms or an aralkyl group (e.g. phenethyl). The nature of the substituents commonly used in the sensitizing carbocyanine dye art and preparation of carbocyanine dyes bearing such substituents is well known to those skilled in the art and is set forth, for example, in The Cyanine Dyes and Related Compounds by Frances M. Hamer (lnterscience Publishers, I964) as well as in US. Pat. No. 2,503,776 and German Pat. Nos. 929,080 and 1,072,765.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE is a spectogram comparing the effects of a dye of the present invention with a prior art dye.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferable sensitizing carbocyanine dyes of the present invention are represented by the following general formula (I):

SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION CROSS-REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part application of Ser. No. 182,505, filed Sept. 2l, 1971, now abandoned, by Akira Sato et al., for spectrally Sensitized Silver Halide Photographic Emulsion.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a silver halide photographic emulsion containing sensitizing dyes, and more particularly to a silver halide emulsion having a high red sensitivity in the range from 635 mg to 665 my.

2. Description of the Prior Art In the art for the manufacture of silver halide photographic emulsions, it is well known that the addition of sensitizing dyes to a silver halide photographic emulsion extends the sensitive wave length region of the emulsion resulting in a spectrally sensitized emulsion. The spectral sensitization depends often on the chemical structure of the sensitizing dye and, above all, the maximum sensitizing peak caused by the J-band is apt to be affected by the chemical structure and introduced substituent of the sensitizing dye. Accordingly, for highly sensitizing a desired sensitive wave length region of a photographic sensitive material, it is thought that CH CH wherein Z and Z' each represents a sulfur or selenium atom; W represents a hydrogen atom, a halogen atom, such as chlorine, bromine, a lower alkyl group, preferably having up to 4 carbon atoms, such as methyl, butyl, etc., or a lower alkoxy group, such as methoxy, ethoxy etc.; and R represents a -y-sulfopropyl, 'y-sulfobutyl or 8-sulfobutyl group.

The sensitizing dyes of the invention are apt to form the J -band and in particular, are useful in increasing the sensitivity in the range from 635 mp. to 665 mp.

Typical chemical structures of the sensitizing dyes of the present invention are shown as follows, but they are Nncocn 2 5 the selection of the proper sensitizing dye is a practically important technique.

SUMMARY OF THE INVENTION kyl group. not restricted only to these examples.

Dze l 2 5 CH=C-CH I: NHCOCI'I3 H SO' c 11 Dye '7 uncoca (cn so CH2CH=CH2 Eye 8 S Ta s cu=c-cac1 r Nl-lCOCl-l (cs so 3 -ca ca ca ca Dxe 9 2% //-cu=c-ca C1 NHCOCHB (CH2) so ca ca ca The sensitizing dyes of the general formula (I) can be synthesized by known methods. With reference to, for example, US. Pat. No. 2,503,776 and German Pat. Nos. 929,080 and 1,072,765, those skilled in the art can synthesize them readily.

An example for the preparation of a typical sensitizing dye of the general formula (I) is described as follows:

SYNTHESIS OF DYE 3 One gram of 5-methyl-3-(7-sulfopropyl)-2-thioproponylmethylene-benzothiazoline is reacted with l g of methyl p-toluene sulfonate at llO-l20C for 2 hours with heating and then treated with ethyl ether to yield a methyl thiocarbinol compound. 1.1 g of 5- acetylarnino-3-ethyl-2-methylbenzothiazolium p-toluene sulfonate is added thereto and dissolved in 160 ml of ethanol, 2 ml of further triethylamine are added and the whole is heated for 3 hours under reflux. After the completion of reaction, the solvent is distilled off and treated with ethyl ether and then with acetone to yield coarse crystals of Dye 3. The coarse crystals are recrystallized from a mixed solvent of chloroform/methanol to yield 500 mg of Dye 3; mp: 296.5C, k 562 mp.

Other sensitizing dyes can be obtained by a synthesis method similar to the process as mentioned above.

The sensitizing dyes used in this invention can spectrally sensitize a silver halide photographic emulsion. In particular, it is effective for extending the spectral sensitive region of gelatin silver halide photographic emulsions. Photographic emulsions containing hydrophilic colloids other than gelatin, for example, agar collodion, water soluble cellulose derivatives, polyvinyl alcohol and other synthetic or natural hydrophilic resins can also be sensitized sufficiently with said sensitizing dyes.

For the emulsion used in this invention, varied silver salts such as silver bromide, iodobromide, chlorobromide and chloroiodobromide can be used.

For the preparation of the sensitized photographic emulsion according to this invention, it is enough to add one or more sensitizing dyes to a photographic emulsion in a common manner. in practice, it is convenient to dissolve the dye in a suitable solvent such as methanol or ethanol and add as a solvent to the emulsion. The amount of said sensitizing dye contained in the emulsion can be varied within a wide range of 5-200 mg/Kg emulsion corresponding to the effect to be desired.

The photographic emulsion of this invention can be further subjected to a hyperor super-sensitization according to a known method.

In the preparation of the photographic emulsion of this invention, additives which are used conventionally, for example, chemical sensitizers, stabilizers, toners, hardeners, surface active agents, anti-foggants, plasticizers, development accelerators, color developers and fluorescent brightening agents can be further added to the emulsion in a common manner.

The photographic emulsion of this invention can be coated onto a suitable support, for example, glass; films of cellulose derivatives, films of synthetic resins, Baryta paper, resin-coated paper and synthetic paper in a common manner.

The present invention will be further illustrated by reference to the following non-limiting example.

EXAMPLE composition was used:

Metol 2 8 Sodium sulfite 100 g Hydroquinone g Borax 2 8 Water to make 1000 cc The red sensitivity and sensitized maximum wave length of the emulsions, which are obtained by adding said sensitizing dyes used in this invention as well as those used as controls, respectively, to said silver iodobromide emulsion, and the absorption maximum wave length of each sensitizing dye used in this invention in methanol are shown in the Table.

TABLE Amount of Maximum Sensitized Examdye added Absorption Maximum Relative ple Dye l0 mol/ Wave Length Wave Length Red No. No. kg (mu) (my) Sensiemulsion) tivity 2 l 8 566 656 l 3 2 8 559 648 I 4 3 10 562 644 I 5 4 I0 567 640 6 5 8 567 654 130 7 6 8 57l 664 8 7 8 563 646 I35 9 8 8 561 648 I20 10 9 8 56! 648 I20 Con trol A 8 560 640 7 B 2 560 640 ll) C 8 556 658 I00 The red sensitivity is shown relatively assuming that the red sensitivity of sensitizing dye C is 100 on the exposure using a Fuji No. 7 Filter. The chemical structural formulae of the sensitizing dyes used as controls are as follows:

The FIGURE shows a spectrogram obtained by using a typical Sensitizing Dye 2 and Control Dye (A), respectively. The excellent characteristics of the sensitizing dyes according to this invention may be understood from the FIGURE. In the FIGURE, curve 2 is obtained using Dye 2 and curve A, dye A, respectively.

What is claimed is: l. A silver halide photographic emulsion containing at least one sensitizing carbocyanine dye of the formula:

l C 2H5 wherein Z and 2' each represents a sulfur or a selenium Dye 2 atom; W represents a hydrogen atom, a halogen atom, a lower alkyl group or a lower alkoxy group; and R represents a y-sulfopropyl, 'y-sulfobutyl or fi-sulfobutyl group, said emulsion having a high red sensitivity, particularly in the range from 635 my to 665 mu.

2. The silver halide photographic emulsion as claimed in claim I, wherein the quantity of the sensitizing dye in said emulsion is within the range of from 5 to 200 mg/Kg emulsion.

3. The silver halide photographic emulsion as claimed in claim 1, wherein said dye is selected from NHCOCH3 the group consisting of NHCOCH3 (cs 50' c 11 N l NHCOCH3 H2) soc 11 l I NHCOCH3 cu so 3 c 11 F ncocu 4. A light-sensitive photographic material comprising atom, W represents a hydrogen atom, a halogen atom, a layer containing the silver halide photographic emula lower alkyl group or a lower alkoxy group; R represion as claimed in claim I. sents a 'y-sulfopropyl. y-sulfobutyl, or fi-sulfobutyl 5. A silver halide photographic emulsion containing group; and represents methyl ethyl, vinyl or n-propyl, at least one sensitizing carbocyanine dye of the forsaid emulsion having ahigh red sensitivity, particularly mula: in the range from 635 my to 665 mp.

wherein Z and Z each represents a sulfur or selenium 

1. A SILVER HALIDE PHOTOGRAPHIC EMULSION CONTAINING AT LEAST ONE SENSITIZING CARBOCYANINE DYE OF THE FOMULA:
 2. The silver halide photographic emulsion as claimed in claim 1, wherein the quantity of the sensitizing dye in said emulsion is within the range of from 5 to 200 mg/Kg emulsion.
 3. The silver halide photographic emulsion as claimed in claim 1, wherein said dye is selected from the group consisting of
 4. A light-sensitive photographic material compriSing a layer containing the silver halide photographic emulsion as claimed in claim
 1. 5. A silver halide photographic emulsion containing at least one sensitizing carbocyanine dye of the formula: 